Metal bridging for joists



Jan. 30, 1962 J. A. REIDELBACH, JR

METAL BRIDGING FOR JOISTS Filed NOV. 9, 1959 ATTORNEYS United The present invention relates to metal bridging adapted to extend diagonally between adjacent surfaces of spaced, parallel joists for the purpose of bracing and stiffening the joists.

It has been common practice in the past to use wood members as bridging for floor joists. The upper ends of such wood members have been nailed adjacent the upper edges of the floor joists prior to laying of the subfioor. At a later time, the lower ends of the wood members have been nailed adjacent the lower edges of the floor joists. Such wood members have served some purpose, but they are objectionable for the reason that their installation is time consuming. Several suggestions have heretofore been made for the use of metal bridging members but, to the best of my knowledge, no such metal bridging members have been entirely free from objection on one ground or another.

Among the objects of the present invention are to provide metal bridging members which require no nailing, which may be quickly and easily installed after the subfloor has been laid or at any other convenient time, which can be standardized to the extent that a single type and size can be used on floors of given specifications, which are of one-piece rigid construction and which tend to become tighter as the joists shrink. A further object of the invention is to provide a metal bridging which is automatically placed under compression during installation and which therefore is in condition to receive the imposed loads and thereby serves to effectively brace and stiffen the floor joists.

The foregoing and other objects and advantages of the invention will be more fully understood by reference to the following specification and the accompanying drawings wherein:

FIGURE 1 is a vertical sectional view through a portion of a floor construction and illustrating a pair of metal bridging members installed;

FIGURE 2 is a top plan view of a metal blank prior to bending or folding;

FIGURE 3 is a side elevational view of a completed bridging prior to installation;

FIGURE 4 is an enlarged sectional view taken in the direction of the arrows along the line 44 of FIGURE 3; and

FIGURE 5 is a fragmentary view illustrating the manner in which the bridging is placed under compression during installation.

FIGURE 1 illustrates a pair of parallel joists 6 and 7 on which a subfioor 8 has been laid. A pair of bridging members 10 and 11 are shown installed between the joists 6 and 7. Since the bridging members 10 and 11 are identical, it will be sufficient to describe the bridging 10.

The blank 12 for production of the bridging member Ill has reinforcing ribs 13 and 14 which extend parallel to the longitudinal axis of the blank. The blank 12 is notched as shown at its left end in FIGURE 2 to provide a central tongue 15 and pointed teeth 16 and 17 at what will be the upper end of the bridging when installed. The rightward end of the blank shown in FIGURE 2 will be the lower end of the completed member when installed. Shallow notches 18 and 19 are formed in the sides of the blank to provide sharp shoulders 20 and 21. The extreme tes Patent 3,918,522 Patented Jan. 30, 1962 2 right end of the blank is provided with a plurality of pointed teeth 22.

The central tongue 15 is folded upwardly about a fold linev 23 to act as a stop member in the manner hereinafter described. The flat heel portion 24 of the blank is folded downwardly at approximately a angle along the fold line 25. The teeth 22 are folded outwardly along the fold line 26 at approximately a 60 angle to the fiat heel portion 24. The intermediate portion of the length of the blank is folded along the longitudinal fold line 27'.

In the completed bridging member, the upper teeth 16. and 17 and the sharp shoulders 20 and 21 lie in a common plane which passes through the central longitudinal axis of the member.

The bridging member 10 can be installed after the subfloor 8 is laid or at any other convenient time by placing its upper teeth 16 and 17 in engagement with the joist 6 adjacent the upper edge thereof and tapping lightly with a hammer against the fiat heel portion 24 adjacent the fold line 25 until the central tongue 15 engages the surface of the joist 6 and acts as a positive stop. The lower end of the bridging member 10 is then pushed upwardly against the surface of the joist 7 until the sharp corners 20 and 21 jam into the surface of joist 7 to temporarily hold the bridging in place. FIGURE 5 illustrates in full lines the relationship of the lower end of the bridging member 10 relative to the joist 7 at this stage of the installation. The flat heel portion 24 can then be tapped with a hammer along the fold line 26 to drive the teeth 22 into the joist 7. The driving of the teeth 22 into the joist will cause the sharp corners 2t) and 21 to slide upwardly along the Surface of the joist 7 and will cause the lower end of the bridging to rise to the broken line position shown in FIGURE 5. This rising of the lower end of the bridging will place the bridging under compression, which is desirable in that it causes the bridging to more effectively reinforce and stiffen the floor. The bridging 11 is installed in a similar manner.

It will be seen that the bridging can be easily and quickly installed without nailing and that the installation can be made in its entirety after the subfloor 8 has been laid. The bridging tends to become tighter as the joists shrink. The compressive stresses are applied to the bridging member 10 along the fold line 23 at the base of the upper teeth 16 and 17 and along the fold line 25 and the sharp corners 20 and 21. It will be seen that these compressive stresses are thus applied to the bridging at positions which lie in a common plane passing through the longitudinal axis of the bridging member. This is desirable in that it reduces any tendency of the bridging to bend.

Very satisfactory bridging according to the invention has been made from 18 gauge zinc-coated sheet steel. The bridging can be completely standardized for any particular joist size and spacing. Floor joist-s are usually either 1 /2 or 1 inches in thickness and are spaced on 16 inch centers. Under these conditions, it is recommended that for 8 inch joists, the distance from the fold line 23 to the fold line 25 be 15% inches. That length should be 16% inches for 10 inch joists and 17% inches for 12 inch joists.

I have illustrated and described the preferred embodiment of the invention. It will be understood that alterations and modifications may be resorted to without departing from the scope of the invention which is defined by the following claim.

Having thus described my invention, I claim:

A metal bridging adapted to extend diagonally between adjacent surfaces of spaced, parallel joists, comprising an elongated body portion of generally V-shape in crosssection with reinforcing ribs extending longitudinally of a said body portion, the upper end of said body portion having a central flat tongue extending upwardly at an angle therefrom, a pointed upper tooth on said upper end of said body portion on each side of said central tongue, the bases of said teeth lying substantially in the plane of said central fiat tongue, said upper teeth lying in a common plane passing through the longitudinal axis of said body portion and being adapted to be driven into a joist adjacent the upper edge thereof until said central tongue engages such joist to act as a stop, the lower end of said body portion terminating in a flat heel portion extending downwardly at approximately a right angle to the longitudinal axis of said body portion and a tooth portion extending outwardly at approximately a sixty degree angle from the lower end of said flat heel portion, said body portion having sharp outwardly facing corners at the upper end of said fiat heel portion, said corners lying in said common plane passing through the longitudinal axis of said body portion and being adapted to jam into the surface of a second joist adjacent the lower edge thereof to temporarily hold the bridging in place, and said tooth portion having a plurality of outwardly facing teeth thereon to facilitate driving said tooth portion into such second joist whereupon the lower end of said bridging will be elevated relative to such second joist and said bridging will become tightly wedged between such joists.

References Cited in the file of this patent UNITED STATES PATENTS 1,642,945 Davidson Sept. 20, 1927 1,655,234 Miller et al. Jan. 3, 1928 1,663,487 Smith et al Mar. 20, 1928 2,624,080 Eichenlaub Jan. 6, 1953 2,803,045 Horner Aug, 20, 1957 2,867,854 Aiken Jan. 13, 1959 

